Package com.google.gerrit.index.query

Class QueryProcessor<T>

java.lang.Object

com.google.gerrit.index.query.QueryProcessor<T>

Direct Known Subclasses:

AccountQueryProcessor, ChangeQueryProcessor, GroupQueryProcessor, ProjectQueryProcessor

public abstract class QueryProcessor<T>
extends Object

Lower-level implementation for executing a single query over a secondary index.

Instances are one-time-use. Other singleton classes should inject a Provider rather than holding on to a single instance.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	QueryProcessor.Metrics

Field Summary

Fields

Modifier and Type	Field	Description
protected int	start

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	QueryProcessor(com.google.gerrit.metrics.MetricMaker metricMaker, SchemaDefinitions<T> schemaDef, IndexConfig indexConfig, IndexCollection<?,T,? extends Index<?,T>> indexes, IndexRewriter<T> rewriter, String limitField, IntSupplier permittedLimit)

Method Summary

Modifier and Type	Method	Description
protected QueryOptions	createOptions(IndexConfig indexConfig, int start, int limit, Set<String> requestedFields)
QueryProcessor<T>	enforceVisibility(boolean enforce)	Specify whether to enforce visibility by filtering out results that are not visible to the user.
protected abstract Predicate<T>	enforceVisibility(Predicate<T> pred)	Invoked after the query was rewritten.
protected abstract String	formatForLogging(T t)
boolean	isDisabled()	Check whether querying should be disabled.
QueryResult<T>	query(Predicate<T> query)	Query for entities that match a structured query.
List<QueryResult<T>>	query(List<Predicate<T>> queries)	Perform multiple queries in parallel.
QueryProcessor<T>	setNoLimit(boolean isNoLimit)
QueryProcessor<T>	setRequestedFields(Set<String> fields)
QueryProcessor<T>	setStart(int n)
QueryProcessor<T>	setUserProvidedLimit(int n)	Set an end-user-provided limit on the number of results returned.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

start

protected int start

Constructor Detail

QueryProcessor

protected QueryProcessor(com.google.gerrit.metrics.MetricMaker metricMaker,
                         SchemaDefinitions<T> schemaDef,
                         IndexConfig indexConfig,
                         IndexCollection<?,T,? extends Index<?,T>> indexes,
                         IndexRewriter<T> rewriter,
                         String limitField,
                         IntSupplier permittedLimit)

Method Detail

setStart

public QueryProcessor<T> setStart(int n)

enforceVisibility

public QueryProcessor<T> enforceVisibility(boolean enforce)

Specify whether to enforce visibility by filtering out results that are not visible to the user.

Enforcing visibility may have performance consequences, as the index system may need to post-filter a large number of results to fill even a modest limit.

If visibility is enforced, the user's queryLimit global capability is also used to bound the total number of results. If this capability is non-positive, this results in the entire query processor being disabled.

Parameters:

enforce - whether to enforce visibility.

Returns:

this.

setUserProvidedLimit

public QueryProcessor<T> setUserProvidedLimit(int n)

Set an end-user-provided limit on the number of results returned.

Since this limit is provided by an end user, it may exceed the limit that they are authorized to use. This is allowed; the processor will take multiple possible limits into account and choose the one that makes the most sense.

Parameters:

n - limit; zero or negative means no limit.

Returns:

this.

setNoLimit

public QueryProcessor<T> setNoLimit(boolean isNoLimit)

setRequestedFields

public QueryProcessor<T> setRequestedFields(Set<String> fields)

query

public QueryResult<T> query(Predicate<T> query)
                     throws QueryParseException

Query for entities that match a structured query.

Parameters:

query - the query.

Returns:

results of the query.

Throws:

QueryParseException

See Also:

query(List)

query

public List<QueryResult<T>> query(List<Predicate<T>> queries)
                           throws QueryParseException

Perform multiple queries in parallel.

If querying is disabled, short-circuits the index and returns empty results. Callers that wish to distinguish this case from a query returning no results from the index may call isDisabled() themselves.

Parameters:

queries - list of queries.

Returns:

results of the queries, one QueryResult per input query, in the same order as the input.

Throws:

QueryParseException

createOptions

protected QueryOptions createOptions(IndexConfig indexConfig,
                                     int start,
                                     int limit,
                                     Set<String> requestedFields)

enforceVisibility

protected abstract Predicate<T> enforceVisibility(Predicate<T> pred)

Invoked after the query was rewritten. Subclasses must overwrite this method to filter out results that are not visible to the calling user.

Parameters:

pred - the query

Returns:

the modified query

isDisabled

public boolean isDisabled()

Check whether querying should be disabled.

Currently, the only condition that can disable the whole query processor is if both visibility is enforced and the user has a non-positive maximum value for the queryLimit capability.

If querying is disabled, all calls to query(Predicate) and query(List) will return empty results. This method can be used if callers wish to distinguish this case from a query returning no results from the index.

Returns:

true if querying should be disabled.

formatForLogging

protected abstract String formatForLogging(T t)